Well, if you read it, it's already pretty nonsensical.
"You may say that, but your maid is listening to you. You sure talk a lot for someone who just sits around and is cared for. "The line is 「で、その小間使いの目の状態はどうなの?ただで直してあげるから貴方は余り喋らない。」
And should be "So, how is the condition of your servant's eyes? I'll treat them for free so let's cut the chatter". How.
Or,
Eirin "I still don't want to die. Besides, I will be preparing the medicine with the Princess's power. It's a shame, but I can't leave it to the Netherworld's hands."Like, what does this even mean when read as-is?
Really this is 「まだ、死にたくは無いわ。それに私は、姫の能力で作られた薬を服用している。残念だけど、冥界のお世話にはなれないのよ」
Which should be "I still don't want to die. Besides, I'm taking the medicine made from the Princess' power. Sorry, but I really can't become the Netherworld's caretaker."
This is
the line that first establishes that Eirin is immortal, but it's so butchered that it loses all its meaning.
Plus we get the "humans can't get there without dying" line, which is terrible in its own right because it spawned the whole "Mokou couldn't be physically present in the Netherworld" thing, but it isn't even the point of the phrase to begin with. 「人間は死ななければならない。」 means "humans must be able to die (lit. 'it shouldn't be that humans can't die')", which is referring to the previous paragraph saying that if humans stopped dying, the Netherworld would never get any new spirits.
like ugggghhhh